A defect in which of the following proteins or complexes would result in the inability of HDL to transfer peripheral tissue cholesterol to circulating LDL?

Question

Quizplus · Accepted Answer

LCAT is responsible for the esterification of cholesterol on HDL, which is necessary for the transfer of cholesterol from peripheral tissues to HDL and subsequently to LDL.  HDLs acquire peripheral tissue-free cholesterol, which is then esterified by HDL-associated LCAT. LCAT is synthesized in the liver and so named because it transfers a fatty acid from the C-2 position of lecithin to the C-3-OH of cholesterol, generating a cholesterol ester and lysolecithin. The activity of LCAT requires interaction with apoA-I, which is found on the surface of HDL. As HDLs migrate through the vasculature, there is an interaction between them and IDL and LDL. This interaction occurs through the action of CETP, which exchanges the cholesterol esters in the HDL for triglycerides from LDL. A loss of LCAT activity would result in the inability of HDL to esterify cholesterol, which would, therefore, result in the inability of HDL to transfer the cholesterol esters to LDL.

A Defect in Which of the Following Proteins or Complexes